Electrostatic precipitator



Oct. 28, 1,952 R. l.. LINCOLN 2,615,529

ELECTROSTATLPC PRECIPITATOR Filled Oct. l, 1948 5 Sheets-Sheet lINVENTOR.

` 27o/qnd L n-veo /11 Oct. 28, 1952 R. L. LINCOLN 2,615,529

ELECTROSTATIC PRECIPITATOR Filed oct. 1, 1948 5 sheets-sheet 2Isa/venan' Poland L. Minto/lz I gawd M Oct. 28, 1952 R. L. LINCOLN2,615,529

ELEcTRosTATIo PRECIPITATOR Filed Oct. l, 1948 5 Sheets-Sheet 5 Oct. 28,1952 R. l.. LlNcoLN 2,615,529

ELEcTRosTATIc PRECIPITATOR 'Filed oct. 1, 194s 5 sheets-sheet 4 Oct. 28,1952 R. LINCOLN ELECTROSTATIC PRECIPITATOR 5 Sheetg-Sheet 5 Filed 0G12.l, 1948 30 Lr -ff Uowney Patented Oct. 28, 1952 UNITED STATESPATENTortica ELECTROSTATIC PRECIPITATOR Roland L. Lincoln, Dover, Mass.,assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Application October 1, 1948, Serial No.52,329

l2 Claims.

. in a gas to be cleaned are givenelectrostatic charges and in thecollector chamber, the charged dust particles are caused to be.attracted to,` and to precipitate upon, dust collecting electrodes.

The dust collecting electrodes usually are closely spaced plates,alternate of which are grounded and the others of which are insulatedfrom the grounded ones. A differencev of potential is establishedbetween the grounded and the insulated plates for establishing anelectric'eld therebetween. Usually the dust Iparticles are givenpositive electrostatic charges in the ionizing chamber, and theinsulated collector plates are positively charged so that the chargeddust particles are attracted to the grounded plates. Experience hasshown, however, that although most of the dust is attracted to thegrounded plates, some is attracted to and adheres to the insulatedplates. Some dust also precipitates upon the ionizer electrodes. adheresthereto and for efficiency in operation has to be removed at intervals.

The most widely used method of cleaning the ionizer and collectorelectrodes is by washing them with a liquid such as water or a light oilsprayed through nozzles upon the electrodes. The collector plates havesubstantial areas and eX- tend substantial distance in the direction ofgas flow and, due to this and to their close spacing, it is diflicult toproject cleaning fluid with sufficient force upon all of their surfacesfor providing adequate cleaning. For adequate cleaning, the liquidshould exert a scouring or wiping eiect upon all surfaces of thecollector plates.

The conventional washing systems have liquid spray nozzles which in somecases, are fixed and in some cases are movable, but in either case areso arranged that most of the liquid which is sprayed strikes the platesurfaces at angles so that its force is dissipated through impact. Fur-The dust precipitated on the electrodes thermore, the washing action isnot sufficiently effective over those surfaces of the plates which arefurthest removed from the spray nozzles.

Another disadvantage of the conventional washing system is that thespray headersr and the piping and other components connected thereto,vare in the gas stream when not in use, and interfere with the gas flowand, as a result, with the collection efficiency.

This invention overcomes the' described' disadvantages of the priorelectrostatic precipitators, i

and has other advantages, which will be described, over the priorprecipitators.

A feature of this invention is that the spray nozzles are arranged to bemoved horizontally along the collector plates so that each nozzle spraysliquid between adjacent plates and parallel to their surfaces therebyeffectively scraping the deposited dust therefrom. i

Another feature of this invention is that the spray nozzles are arrangedto be moved horizontally across the gas entering and the gasleaving endsof the collector plates, the nozzles at the upstream ends of theplatesspraying liquid Atowards the downstream ends thereof, and the.nozzles at the downstream ends of the plates spraying liquid towards theupstream ends thereof, the two sets of nozzles effectively washingandfcleaning all of the plate surfaces.

Another feature of the inventionis thatgthe spray header carrying thenozzles at theupstream ends of the collector plates also has nozzleswhich spray cleaning liquid uponjthefionizer electrodes.

Another feature 0f this invention is that'.` during the periods theprecipitator is cleaning. gas, the spray headers and their pipes andother components are completely removed from the gas stream.

Another feature of this invention is that an eicient compactelectrostatic precipitator is provided which is self-contained in thatit encloses its own separate ionizing, collection, and washingapparatus, with louvres in its upstream, Hand downstream ends which areclosed when theelectrodes are washed, and which is .adapted to beoperated in series with .other similar precipitators so that one at atime can be removed=from service for cleaning while the Othersremain` inservice. A V' Another feature of the invention is that the collectorchamber comprises a plurality of similar, compact collector cells whichare easily removed and installed, and which can readily be stacked oneabove the other and/or one alongside the other` for providing anydesired size of collector chamber.

An object of the invention is to provide a compact, self-containedelectrostatic precipitator having its individual ionizing electrodes,collector electrodes, and electrode washingr mechanism whereby it can becombined with other similar precipitators for providing a dustcollection system of any desired size.

Another object of the invention is to provide an improved electrodewashing system for the electrodes of an electrostatic precipitator.

Another object of the invention is to provide electrode washingcomponents for an electrostatic precipitator which are isolated from thegas stream when the precipitator is operated to clean a gas.

The invention will now be described with reference to the drawing ofwhich:

Fig. 1 is a perspective view of an electrostatic precipitator embodyingthis invention, with a portion at the front and one side removed forillustrating the arrangement of the inner components;

Fig. 2 is a plan View, in section, of the precipitator, the sectionbeing taken along the lines 2-2 of Fig. 3; I

Fig. 3 is a side elevation, in section, of the precipitator, the sectionbeing taken along the lines 3-3 of Fig. 2;

Fig. 4 is a section, of the precipitator, the section being taken alongthe lines d-- of Fig. 3, and

Fig. 5 is a front elevation corresponding to Fig. 4 but illustrates theposition of the electrode washing equipment removed from the gas streamwhen not in use.

The precipitator as illustrated has a cubical shape with a structuralsteel frame I!! and sheet metal sides I I, two sides being open for theentry and exit of gas. The gas entering end of the precipitator has theplurality of spaced, inlet louvres I2 therein which are interconnectedby the linkage I5 so that they can be simultaneously adjusted to open orclosed positions.

The structural steel frame I'I extends vertically at the longitudinaland transverse center of the precipitator and has the spaced outwardlyextending shelves i8 thereon. The opposite sides of the frame-work ofthe precipitator have the shelves I9 thereon which are aligned withcorresponding shelves I8. The collector cells 26 are placed on theshelves I8 and I9. ln the embodiment illustrated, the collector chambercontains twelve cells arranged in two vertical rows with six cells ineach row stacked one above the other. The collector cells are similarand are of the type disclosed in the E. L. Richardson Patent No.2,535,696. The cells are self-contained, are compact and light inweight, and can easily be removed from, and installed in, the collectorchamber, as for servicing or replacement. As illustrated most clearly byFigs. l, 2, and e, the collector plates 2I of the cells 2S are arrangedvertically, the plates of each underlying cell being in verticalalignment with the corresponding plates or the similar cell locatedabove it.

Located downstream of the inlet louvres I2 is the ionizing chamber 24which contains the plurality of vertically extending, relatively large,

tubular ionizer electrodes between which are suspended the ionizer wires23 carried on the ends of the supports 25, the supports 2G beingattached to the bars 2l, which in turn are supported by the insulators28. This ionizer electrode arrangement is conventional.

The equipment for washing the ionizer electrodes and the collectorplates will now be described. Located between the ionizer electrodes andthe collector cells are the upper and lower, threaded rods and SIrespectively. These rods are located above and below respectively, thecollector chamber, and are completely out of the gas stream passingbetween the ionizer and collector chambers.

The upper and lower threaded rods and 36 are arranged between thecollector cells 2U and the outlet louvres I4, these rods also being outof the gas stream, the upper rod 35 being in horizontal alignment withthe upper rod 30, and the lower rod 35 being in horizontal alignmentwith the lower rod 3I.

The rod 3D has threaded thereon the ntting 38 which is attached to theupper, closed end of the liquid header 3B. The closed, lower end of theheader 39 has attached thereto the fitting IQ which is threaded on thelower rod 3l.

The header 39 has the spaced downstream spray nozzles l-l, two of whichface the upstream ends of the plates of each collector cell 2U. Theheader 3S also has the spaced, vertically aligned, upstream, spraynozzles 4I, each of Which are arranged to wash the entire surfaces ofthe ionizer electrodes.

The ntting :l5 is threaded onto the downstream, upper, threaded rod 35and is attached to the upper, closed end of the liquid header IIB. Thefitting 67 is attached to the lower, closed end of the header 4S, and isthreaded onto the lower, downstream, threaded rod 36. The header 4B hasthe spaced, vertically aligned, nozzles i8 extending upstream therefrom,two of these nozzles being in alignment with the downstream ends of thecollector plates of each collector cell 2U.

The upstream header 39 has the pipe fitting 50 extending therefrom, andwhich is threaded into the swivel pipe' connection 5I which, injturn, isthreaded on the upper end of the pipe 52. The lower end of the pipe 52and the lower end of the pipe 53 are connected together through a swivelpipe fitting 54. The upper end of the pipe 53 is connected to the liquidsupply pipe 54.

The downstream header 4B has the pipe fitting 55 extending therefrom,and which is threaded into the swivel pipe connection 56, which, inturn, is threaded on the upper end of the pipe 57. The lower end or" thepipe 5l, and the lower end of the pipe 5S are connected together througha swivel pipe connection 59. The upper end of the pipe 58 is connectedto the supply pipe 5d.

Arranged at one side of the gas passage through the precipitator, theleft-hand side facing Figs. l, 3, and 5 of the drawing, is the electricmotor 55 which is connected to the speed reducing gear mechanism GI bythe belt 62. The mechanism 6I has a sprocket 63 with which the chain 64meshes. The chain @d extends around and meshes with the sprocket G5 onone end of the upper threaded rod 35, extends around and meshes with thesprocket 65 cn the corresponding end of the upper, downstream, threadedrod 35, then meshes with a similar sprocket on the corresponding end ofthe downstream, threaded rod 3'6, and then meshes with the sprocket 58on the corresponding end of the upstream, lower, threaded rod BI.

T'Ihegchainil "is an nendless chain, and as it .is

'rotated throughthe gear-reducing mechanism 6I by themotor 60, fitfrotates simultaneously the threaddgrods A30,531, 35, and 36. vThisrotation .of the threaded rods causeshorizontal movev:nient ofthe'ttings-38 and Vl!!! attached to the upstream headerf39,van`d thedownstream'ttings Cl-a'nd'tl attache'dtothe downstreamheader d'5,

{causing corresponding horizontal movement of the'twoheaders. l Y

"Normally, when the electrostatic precipitator -isoperating tooleangas,the inlet louvres l2 and lthe-outlet louvres `l'4 -willbe open in theposi- -tions illustrated-most clearly by Fig. 13. At this 'time,theheaders will be in the-passage 'l0 v(Fig.

f4), -Whichis atthe left hand side -of the gas K passage through vtheprecipitator, in lthe position -illustrated by .the full lines of Fig-5.The dashed L)lines .illustrating vthe upstream header kand the.piping-of Fig. f5, 4show another position of the 'header when it isl:being used to spray :cleaning liquid between the-collector plates andon the ioniz'er-electrodes. K

iFigs. 11,12, iand-4l illustrate one position of the upstream v.and-downstream headers when they =arebei`ng used to clean the-electrodes.

lshould be understood" that the 'invention is not limited tothe exactapparatus and arrangement of apparatus illustrated, las modificationstherefrom may be suggestedby those skilled in the art without departurefrom' the essence of the in.-

` vention.

What is claimed-is: 1.*An' electrostatic precipitator comprising acasinghaving a gas inlet and a gas outlet and a `lpai'ro'f verticalsides, a plurality of substantially vertically extending, r spaced apartcollector plates supported in said .casing betweensaidinlet and'.outletland .parallel said sides, said .casing having an open spacebetween one of said vertical sides `and `the outermost ofsaid plates atone side of :said plates whichis out of alignment with said inlet :andplates, a .substantially vertically extendingliquid header lhaving .aplurality of spray nozzles .for .spraying liquid in between adjacent.'ofsaid plates, and means for moving said header .substantiallyhorizontally back and forth along said plates yfor washing same, and formoving s aid header into said space following the washingoffsaid plates,said header 'whenin said space :being out of the gas streamflowing fromsaid finlet .between 'said plates.

` l2. An'velectrostatic precipitator having `a casing .I 'The`sump'80'is1provided in 'the .lower .portion fof vtheprecipitator fandis adapted to be drained through the drainfconnection 8|.

lAftera period of operation, longenough to have'caused-enough"sufficient dust to have beencollecte'dthat cleaning -isrequired, :then the high voltage current .applied to the ionizer andcollector electrodesis-removed,'and theinlet louvres l2 'and theoutletllouvres I4 are closed. This can ibe done manually Vor'by suitableautomatic con- 'trols. The cleaning liquid which may be a light "oil vasis commonly fused lfor .cleaning the elec- :trodes of lelectrostaticprecipitators is supplied into the pipe 54. The energizing circuit ofthe vmctortis thenclosed, causing it to rotate. This causes the chain56'4 lto revolve, and .causes fthe headers 39 land dl to move from theposition, shown vby the full vlines cf Fig. 5,horizontally 'towardstheright-hand side of the precipitator.

' This causes theupstream nozzlesll of the header 39 to wash the dustadhering to the ionizing electrodes therefrom. The downstream nozzlesy vi0 of the upstream header 3'9 moverslowly across the upstream lends ofthe 'collector plates 12| r of vthe-collector .cells 20, and spray thecleaning. liquidin between the .plates Vparallelto their sur-v faces, so.thatthe energy ofthe spray is expended having .a gas inlet and a gasoutlet `and a pair *of vertical Sides, .a plurality of substantiallyvertically extending, :spaced apart collector'plates .supported in saidcasing between said inlet and outlet and parallel said sides, Vsaidcasing havin'scouring or wiping 'the plate surfaces. Since the sprayfrom the downstream nozzles vllllzof the yupstream header 39 may not beleective `to completelyclean the downstream portions ofthe collectorplates, the vupstreamnozz'les 48 .of the downstream header '46 sprayliquid into the spaces l between the downstream `ends -of .adjacent col-Ilector plates, and parallel to the `plate surfaces asiin the case ofthe nozzles 40, thus scouring or wiping Vthe ldownstream .portions of`the plates.

The swivel .connections 5|, 54, 56, and .59 Eper-` mit liquid tobe'supplied'to the headers' through i their supply piping, as they 'are:moved back and .forth during'the washing operation. i

.In one actual installationv embodying this invention, it `was foundthat the plates could be adequately cleaned by moving the spray headiers from their startling position outside the gas .stream,.;past thesurfaces ofthe D1aBS,-andback A"again to their starting position. Whileone embodiment :of the invention has vbeen described for the purpose ofillustration, it

in'g .'anopen .space :between one :of said vertical :sidesand theoutermost of .said plates vat one ,side of said plates which is out tofalignment with :said-inletand plates, a substantially vertically'extending liquid header havinga plurality .of .spray .nozzles forspraying liquid in .between adjacent of said plates, said header havingends extending above and below said plates, and means ...at said endsofv said header for moving same sub- `stantially .horizontally back andforth along said platesv for washing same, and for .moving said headerinto said open space when the washing is completed, said .header when in.said space being out of the :gas stream owing from said inlet .betweensaid plates.

i i3.An electrostatic precipitator comprising a .casing having openends, one forming a gas inlet and the other forming a gas outlet,l.ionizer electrodes in said casing adjacent said inlet,

a .plurality of substantially vertically extending collectorplatesinsaid casing between said elec- "..trodesand saidoutlet, asubstantially .vertically 1.ex`tending liquid Jheader movable betweensaid .electrodes and said plates, said lheader having a plurality ofdownstream nozzles arranged to spray 'liquid `.between said collectorplates, 'and having a :plurality of upstream .spray nozzles arranged to.spray .liquid 'upon said electrodes, and means for moving saidheadersubstantially horizontally between. said electrodes. and saidplates.

.4..An1el'ectrostatio precipitator comprising a .casing .havingopen'ends, one formingla gas inlet .and theother forming a gasoutlet,'ionizer electrodes .in said casingadjacent said inlet, apluvirality `of substantially vertically extending col- ;lectorfplatesin'rsaid casing between 'said electrodes and said outlet, asubstantially vertically extending liquid header movable Ybetween said`electrodes and .said plates, said vheader having. a

pluralityof downstream nozzles arranged to spray liquid between saidcollector plates, and having .aplurality of'upstreamspraynozzles'arranged to spray vliquid .uponsaid electrodes, said headerhaving ends extending; above and below vvsaid plates, and means at saidends, osaidheader for moving said header substantially horizontallybetween said electrodes and said plates.

5.*An electrostatic precipitator comprising a casing having open ends,one forming a` gas yinlet and the other forming a gas outlet, saidcasing having an open space therein at one side thereof, ionizerelectrodes in said casing adjacent said inlet, a plurality ofsubstantially vertically explates, and having a plurality of upstreamspray nozzles arranged to spray liquid upon said electrodes, andmeansfor moving said header substantially horizontally between saidelectrodes and said plates for washing said plates, and for moving saidheader into said space when the washing is completed.

6. An electrostatic precipitator comprising a casing having open ends,one forming a gas inlet and the other forming a gas' outlet, said casinghaving an open space therein at one side thereof, ionizer electrodes in`said casing adjacent said inlet, a plurality of substantially.vertically extending collector plates in said casing between saidelectrodes and said outlet,y asubstantially vertically extending liquidheader movable 'between said electrodes and said plates, said headerhaving a plurality of downstream nozzles' arranged to spray liquidbetween said collector plates, and having a plurality ofupstream spraynozzles arranged to spray liquid upon said electrodes, said headerhaving-ends extending above ,8 l i `plates and said outlet and having aplurality of upstream spray nozzles arranged to sprayvjliquid betweensaid plates, and means. fori moving said 'headers substantiallyhorizontally.-along- Hsaid ,plates i precipitator vcomprising a 9. Anelectrostatic msnghaving openv ends, one forming a* gas inlet y and theother forming a gas outlet, ionizer elecrodes in said casing adjacentsaid inlet, aplurality of substantially vertically extending coli lectorplates in said casing between said electrodes and said outlet, asubstantially vertically extending liquid header movable between said,electrodes and said plates, said-header having a; plurality of ldownstream Ynozzles arranged to spray liquidfbetween saidcollectorplates, aseeond substantially vertically extendingA headermovable between said plates and said outlet and vhavinga plurality ofupstream spray nozzles arranged rto spray liquid between said plates,said headers having ends extendingabove andv below platesg and meansat ysaid ends of said headers-for moving said headers substantiallyhorizontally along said platea.

` outlet and having a plurality of upstream spray and below said plates,and means Vat said ends of said header for moving'said headersubstantially horizontally between said electrodes and said plates forwashing said plates, and for moving said header into said space when thewashing is completed. Y u

7. An electrostatic precipitator comprising a casing having open ends,one forming a gas inlet and the other forming a gas outlet,ionizer-electrodes in said casing adjacent said inleta plurality ofsubstantially vertically extending collector plates in said casingbetween said electrodes and said outlet, a substantially verticallyextending liquid header movable between said electrodes and said plates,said header having a plurality nozzles arranged to spray liquid betweensaid plates, and means for moving said headers substantiallyhorizontally along said plates for washing said plates, and for movingsaid headers into said space when the washing is completed.

ll. An electrostatic precipitator comprising a casing having open ends,oneforming-a-gas inlet and the other forming a gas outlet; said cas--ing having an open space therein at one `side thereof, ionizerelectrodes in said casing` adjacent of downstream nozzles arranged tospray liquid n rality of substantially vertically extending col-- lectorplates in said casing between said electrodes and said outlet, asubstantially vertically extending liquid header movable between saidelectrodes and said plates, said header having a plurality of downstreamnozzles arranged to spray liquid between said collector plates, andhaving `a plurality of upstream spray nozzles arranged to spray liquidupon said electrodes, a second substantially vertically extending headermovable between said said inlet, a plurality of substantially verticallyextending collector plates in said ycasing Vbetween said electrodes andsaid outlet, a substantially vertically extending liquid header movablebetweensaid electrodes and said plates, said header having a pluralityof downstream vnozzles arranged to spray liquid between said collectorplates, a second substantially vertically` extending header movablebetween said plates and said outlet and having `a plurality of upstreamspray nozzles arranged to spray liquid betweensaid plates, said headershaving ends'extending above and below said plates, and means atysaidends of said headersfor moving said headersisub'stantially`horizontally along said plates forzwashing said plates, and for movingsaid headers into said space when the washing is completed.-v v

l2. An velectrostatic precipitator comprising a casing having open ends,one forming a gas inlet and the. other forming a'gas` outlet, vsaidvcasing having an open space therein at one side thereof, ionizerelectrodes in said casing adjacent said inlet, a plurality ofsubstantially vertically extending collector plates in saidcasing'betwecn said electrodes and said outlet, a substantiallyvertically extending liquid header-movable between said electrodes andsaid plates, said header having a plurality of downstream nozzlesarranged to spray liquid between said collector plates, and having aplurality of upstream sp-ray nozzles arranged to spray liquid upon saidelectrodes, a second substantially vertically extending header movablebetween said plates and said outlet and having a plurality of upstreamspray nozzles arranged to spray liquid between said plates, and meansfor moving said headers substantially horizontally along said plates,for washing said plates, and for moving said headers into said spacewhen the washing is completed.

ROLAND L. LINCOLN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date Craft Apr. 8, 1941 Peggv Nov. 2,1943

